Amplifier system



Oct. 3, 1933. 'r. H. NAKKEN 1,928,760

AMPLIFIER SYSTEM Filed May 21, 1929 |||||||||||||||||fl|||||l||||||||||||||||||| B A III g a R ==7 INVENTOR I N i THEDDDBUS H. NHBKEN I ATTORNEY Patented Oct. 3, 1933 azawso AMPLIFIER. SYSTEM Theodor-us H. Nakken, Brooklyn, N. Y., assignor to Nakken Patents Corporation, a corporation of Delaware Application May 21, 1929. Serial No. 364,877-

3 Claims. (Cl. 179-171) 'The object of this invention is to improve amplification of feeble energy manifestations through the medium of the thermionic triode amplifiers. The invention utilizes principles necessitating a floating of the electric potentials of the preceding cathodes relatively to succeed ing cathodes and perforce of circumstances utilizes the heater type of-cathode.

The above and further objects of the inven- 13 tion will be pointed out more in detail in the accompanying claims which are directed to the illustrative embodiment of the invention described in the following specification. in connection with the accompanying drawing solelyfor the pur- 35 poses of illustration and not limitation.

In the drawing, the single figure is a diagram illustrating the invention. Three triode amplifiers A, A" and A' are arranged in a series to effect geometric amplification. Each amplifier 29 comprises a cathode F with its heating element f, a grid G and plate P. A suitable transformer T supplies the heating energy for the heater I from one secondary coil 1 for the heater of triodes A and A" and forms a separate coil 2 for the filament f for triode A', it being understood that this cathode may take the form of the filament type illustrated because of the fact that this cathode is not one of the floating potential type being connected directly to the B-battery B, al-

s olthough of course it is to be understood that it may be of the heater type illustrated for cathodes A and A". What is meant by floating potential type has to do with the fact that the heating element I is insulated from the cathode F and also it heats it. The filament I may remain at ground potential while cathode F becomes either more positive or more negative than ground potential.

3 illustrates suitable impedance for the plate circuit 4 of triode A' which may take the form of the field winding of a dynamic loud speaker and serves to conduct the D. C. portion of the plate current, the A. C. portion of which is of course filtered out and passed through a suitable translating device 5 which may take the form of the movable coil of a dynamic loud speaker. The

filtering condenser 6 is employed to cooperate with the choke 3 and the usual B-battery of suitable potential for the tube in question is employed. It is to be understood that although the plate circuit 4 is shown connected to the terminal positive end of battery B, it may be connected to any intermediate point and the battery enlarged if desired to meet any desired potential requirement for one of the preceding plates of the series.

In the drawing illustrated, the plates of all triodes are shown conductively connected by conductors "7 and 8 and the plate circuit 4, conductors '7 and 8 actually being tapped off of the B-battery at any suitable positive potential point or points.

The cathode of each preceding tube such as the cathode F of the tube A is conductively connected with the grid G of the succeeding triode such as the grid G of triode A". These conductive connections are denoted 10' and 10". 6

A high impedance made up primarily of selfinduction and having relatively low ohmic resistance short-circuits the cathode and the grid of each triode of the series expect that of the first triode. Such impedances are indicated by 11' and 11-" in the diagram.

Thus against the normal plate current for each plate circuit of each of the triodes the impedances 11' and 11" offer no opposition so far as the direct current component thereof is concerned and three plate circuits may be traced: first, plate circuit 4 for triode amplifier A; second, plate circuit 8 for triode amplifier A" which includes B-battery B, wire 12", impedance 11", wire 10", cathode to plate of triode A" and wire 8 back to B-battery. A similar circuit including impedance 11 in series with impedance 11" involves triode A and wire 7. For the normal D.C. flow in these plate circuits a slight fall of potential across the impedances 11" and 11' occurs in accordance with Ohms law whereby the grid G of triode A is normally slightly more positive than its cathode and likewise the grid G of triode A" is slightly more positive than its cathode.

Thus for no signal condition, that is, with no pulsating or alternating impulses floating through the amplifier, all cathodes are about at the same potential, each preceding one in the series being slightly more positive than each succeeding one.

In the diagram illustrated the initiator of energy variations to be amplified is shown in the form of a photo-electric cell 20 having an anode 21 conductively connected to the grid of the first triode and a cathode body 22 connected to the choke 23 which in turn is connected to the minus terminal of stimulating battery 24, the positive terminal of which is connected through choke 25 to conductor 10'. The other terminals of chokes 23 and 25 are cross-connected through by-pass condenser 26. A measured rate discharging means for electrons from the insulated electro-static system including grid G, wire 27 and anode 21 is shown in the form of a leak resistance 28.

For conditions of no light falling upon the photo-electric cell 20, the potential of the grid G and its insulated electro-static system is the same as the potential of its associated cathode 1''. For

the hook-up illustrated, if a light impulse reach the cathode body 22, an instantaneous surge of 5 electrons in proportion to the impulse of light enem collect upon the anode 21 and by reason of the fact that they can not fiow oil at more than the measured rate limitation of leak resistance 28 cause a lowering of potential or a more minus character for the grid G of this triode than is the potential character of its cathode I". This effects a decrease in the fiow of electrons to the plate P of triode A and, in other words, a reduced rate of emission of electrons from cathode F. The normal outflow of electrons from the electro-static system including cathode I", conductor and grid G of triode A" is checked and the potential of this system becomes more minus but in an amount amplified over the potential change upon grid G corresponding to the amplification factor of the triode. Grid G of the second triode now having become more minus, its plate circuit current is checked and its cathode draws electrons at a reduced rate from the grid of the last tube of the series resulting in a geometrically amplified reduction in the plate current of triode A'. It is thus to be seen that in accordance with this ,system large instantaneous changes of electron emission have their effect conveyed directly to the grid of a succeeding triode for purposes of amplification.

In order to isolate the battery 24 from its retarding effect upon the desired floating of the potential for cathode F of the first tube the chokes 23 and 24 are effected. It is, of course, to be understood that this system is designed primarily for the amplification of pulsating or alternating energy impulses such as those derived from light impulses and is not a photometer for the purpose of measuring in terms of an electric current the constant light value of a source of light.

It is also to be understood that the converse of the photo-electric cell circuit illustrated may be employed in which the battery 24 should be shifted plus for minus and the anode 21 and the cathode 22 interchanged. With such connections the instantaneous drawing of electrons from the cathode body 22 would effect an increase in the positive direction for the potential of the grid G of the first tube by reason of the fact that a sudden drawing out of electrons was the response to alight shock. Following through the functioning of the system in response to the sudden drawing out of electrons from the grid G of triode A, the resulting more positive character for grid G causes an increased electron fiow within triode A from cathode F. The only source from which it can instantaneously obtain electrons is the grid of triode A" which therefore becomes more positive in accordance with the amplification factor of tube A. The choke 11' can not respond rapidly enough to supply this instantaneous demand for electrons. The effect then upon triode A" is to cause an increase in electron emission from its cathode which has to be supplied from the grid of triode A', again in accordance with the amplification factor of triode A". The'geometrically increased positive character for the grid of triode A effects a powerful surge in its plate circuit through the translating device 5. During this functioning the potential of wire 10' and the connected cathode F and the connected grid of triode A" floats electrostatically, its actual potential relatively to outside things varying or floating in proportion to the negative charge or quantity of electrons actually contained within it as an isolated system at each particular instant.

Although I have illustrated a preferred embodiment of my invention and the same only in diagram, it is to be understood that I contemplate all natural equivalents falling under the terms of my claims and the employment of all approved instrumentalities and means now known to the art.

What I claim and desire to secure by United States Letters Patent is:

1. An amplifier system comprising a plurality of amplifier units, each said unit comprising a grid, a cathode and a plate; a source of potential; a translating device; a power circuit including said source of potential, said translating device, and the cathode and the plate of the last said unit, all in series; a conductive connection between the plate of said circuit and each plate of the other said units; a conductive connection between the cathode of each said unit and the grid of the immediately succeeding said unit; a high impedance of low ohmic resistance connecting the grid with the cathode of each of said units except the firstsaid unit; provisions maintaining the cathodes of all of said units except the cathode of the last said unit insulated from said source of potential and from ground except through the signal functioning parts of said system, all whereby an increase in the emission of electrons from the cathode of a preceding unit renders the con-' nected grid of the next said unit more positive, and whereby a decrease in the emission of electrons from the cathode of a preceding unit renders the connected grid of the next succeeding unit more negative.

2. The system as characterized in claim 1 and further characterized by the fact that means substantially without coupling with other parts of the system is provided for varying the relative potential between the cathode and the grid of said first unit, while permitting the potential of the cathode of said first unit to move up and down in potential relatively to the potential of the cathode of said last unit.

3. An amplifier system including a plurality of thermionic triode amplifiers in series array; a plate circuit for the last said triode amplifier including a source of direct current potential connected to the cathode of said triode; provisions whereby the cathode potential of the first said triode of said series may vary between a higher and a lower potential level, said provisions including insulating and spacing to effect freedom from capacity coupling with other parts of said system; an input circuit for said first triode including a direct current source; and means including a high impedance connected between one terminal of said source and said cathode of said first triode for permitting the potential of the cathode of said first triode to move up and down independently of the electrostatic potential of said battery and up and down relatively to the electrostatic potential of said source of potential included in said plate circuit. 1

THEODORUS H. NAKKEN. 

